Tackling disposal of greenhouse gas emissions

Feb. 6, 2006

KALAMAZOO--As evidence of global warming mounts across the
globe, researchers at Western Michigan University are investigating
a new way to stem its spread-- a way that could end up making
a lot of money for the state of Michigan.

It's called geological carbon sequestration, a process that
essentially liquefies carbon dioxide and disposes it thousands
of feet beneath the ground. With the help of grants from the
U.S. Department of Energy, researchers at WMU's Core Research
Laboratory are investigating the feasibility of burying the harmless
gas in the billions of cubic feet of porous rock that lie deep
beneath Michigan's farm fields and forests.

Odorless and tasteless, carbon dioxide poses no direct health
risk to humans and is used by plants in photosynthesis. But most
scientists agree that the gas is wreaking havoc on the world's
climate. When released into the atmosphere in massive quantities,
mainly through the burning of fossil fuels, carbon dioxide molecules
deflect solar radiation back to the earth, resulting in a gradual,
but steady warming of the atmosphere.

Most of the world's industrialized nations have agreed to
limits on greenhouse gas emissions. So far, the Bush administration
has declined to sign on to the limits, known as the Kyoto Protocol.
But many government officials and scientists recognize that it's
only a matter of time before the United States, the No. 1 producer
of greenhouse gases, has to take decisive action to limit emissions.

And that's where geological carbon sequestration comes in.

"The state of Michigan possess a substantial volume of
underground void space," says Dr. David Barnes, the WMU
associate professor of geosciences who is leading the research
effort. "This huge volume of sub-surface space provides
a potential repository for waste materials. This is a real economic
opportunity for the state of Michigan."

States like Michigan with huge underground reserves of porous
rock could become sites for large, modern power plants, where
CO2 is captured, liquefied and pumped into the ground, Barnes
says. The state would benefit from the jobs that would be created
and the additional tax revenue.

WMU began the first phase of its CO2 sequestration research
project in mid-2004 with the first of two grants from the Department
of Energy. The first phase, funded by a $100,000 grant, ran through
mid-2005 and was followed by a second DOE grant for $280,000
to begin a second phase. Michigan is part of the DOE's Midwest
region carbon dioxide sequestration program. Barnes is being
assisted in WMU's project by co-investigators Dr. G. Michael
Grammer, WMU associate professor of geosciences, and Dr. William
B. Harrison, WMU professor emeritus of geosciences and Core Research
Laboratory director.

The project is assessing the feasibility of capturing CO2
from large-scale emitters, such as ethanol plants, cement factories
and, in particular, coal-fired power plants, compressing the
CO2 into a dense, fluid-like state, then injecting it deep into
the ground. The porous rock strata to be used are far deeper
than any fresh water aquifers used for drinking water to eliminate
any threat to fresh water quality.

The volume of CO2 being emitted into the atmosphere is in
the billions of tons annually, Barnes says. But even at current
levels, researchers estimate there is enough porous rock in the
Midwest region to store CO2 from large-source emitters for some
600 years. Pumping it deep into the ground also will maintain
the pressure needed to keep the CO2 in a liquid form.

Researchers have proposed a pilot project in an area of natural
gas well fields in northern lower Michigan. The natural gas being
extracted there is high in CO2 and, as it is processed, the CO2
is being vented into the atmosphere. The plan is to capture the
CO2, pressurize it and pump it into the ground. The project will
take some three or four years to complete, in part because researchers
want to be sure that the gas remains pressurized and does not
escape back into the atmosphere.

CO2 sequestration can have a secondary benefit by enhancing
oil recovery, Barnes says. In places where oil has been extracted
and production through natural pressure drive is depleted, CO2
could be pumped into the field and used to force additional oil
from the ground. In fact, an oil producer in northern Michigan
is doing just that.

WMU is part of one of 14 consortia in the nation studying
various aspects of carbon sequestration. The Midwest region is
being overseen by Battelle, a global science and technology company
headquartered in Columbus, Ohio, that develops and commercializes
new technology. Battelle has been awarded $14 million by the
Department of Energy to investigate CO2 sequestration and has
contracted with U.S. State Geologic Surveys in six states and
WMU to carry out studies in the Midwest.

If CO2 emissions become regulated, which seems likely, companies
would be interested in building new power plants located where
the gas can be cheaply and easily disposed of on site. Michigan,
with its vast reserves of porous rock, would provide an ideal
place for such modernized plants.

Michigan ranks 13th among oil and natural gas producing states
in the nation, Barnes says. The states ranking above Michigan
probably would have more porous rock, but it's also a matter
of which area best serves the power requirements of a given region.
A power plant in Michigan could serve many large metropolitan
areas nearby.

The environmental community has been somewhat unenthusiastic
about the idea, Barnes admits. But the gas would be pumped to
depths ranging from about 2,500 feet to as much as 10,000 feet
beneath the surface and would pose no threat to wells used for
drinking water.

Barnes says geological carbon sequestration offers the potential
for an economically viable, near-term alternative to venting
CO2 into the atmosphere from large point sources.

"Geological carbon sequestration should be considered
as only one technology in a suite of technologies that we must
develop to address environmental concerns over CO2 emissions,"
Barnes says. "Maintaining our capability to provide relatively
inexpensive power is a critical component to security and stability
in modern industrialized societies and is especially important
during the inevitable transition period to alternative methods
for industrial scale power generation."